Hello and welcome to e health forum.
The most likely cause of your symptoms could be due to stress and fatigue, after a delivery.
A few days of rest and relaxation will be very helpful to reduce your symptoms.
In the mean time, you can take OTC medications like tylenol, which are safe medications to reduce your headache, during lactation.
If your symptoms persist, even after such measures, you may need to consult a doctor to rule out issues like migraine.
I hope this helps.